Machine for folding and locking carton blanks



Dec. 16, 1958 JOHNSON ET AL MACHINE FOR FOLDING AND LOCKING CARTON BLANKS Filed May 19, 1955 5 Sheets-Sheet l rma IV Dec. 16, 1958 JOHNSON ETAL 2,864,287

MACHINE FOR FOLDING AND LOCKING CARTON BLANKS Filed May 19, 1955 3 Sheets-Sheet 3 non FOLDING AND LOCKING CARTONBLANKS Al Johnson and Fred Gauger, Stockton, Calif., assiguors to. Al Johnson, doing business as Valley Pattern & Mfg. Co., Stockton, Calif.

Application May 19, 1955,.Serial No. 509,649

1 Claim. c1. 93-51 I MACHINE The invention relates generally to machines for folding and locking carton blanks and more particularly to machines of this kind which are operated by hand or by other rudimentary types of prime movers.

It is an object of the invention to provide a carton folding and locking machine which is sturdy, reliable, and simple to operate, but which is capable of converting into carton form, in unit time, a considerably greater number of cartons than is possible by hand folding.

It is another object of the invention to'provide a hand operated carton folding and locking machine which is relatively inexpensive and durable and which is therefore capable of producing a substantial number of cartons per dollar of original cost and per dollar of upkeep and maintenance expense. i

It is still another object of the invention to provide a machine which has but relatively few moving parts and which, therefore, requires but a minimum of upkeep, repairand maintenance effort and expense.

It is a further object of the invention to provide a carton folding and locking machine which has no moving parts on the plunger to get out of order and which, therefore, minimizes shut-down time and other non-productive periods resulting from the need to repair the movable plunger parts customarily encountered in macln'nes of this general nature.

It is yet another object of the invention to provide a generally improved machine for folding and locking carton blanks.

Other objects, together with the foregoing, are attained in the embodiment described in the accompanying description and shown in the accompanying drawings in which:

Figure l is a perspective of the carton folding and locking machine and showing on the apron thereof a typica carton blank.

Figure 2 is a plan view of the carton blank illustrated in Figure 1, to an enlarged scale, and with a portion of the figure being broken away to reduce the extent thereof.

- Figure 3 is a plan view of the die and showing the plunger in-a position vertically above the central die aper- 'ture, the left hand portion of the plunger being broken 'away more clearly to disclose the construction of the die. Figure 4 is a median vertical section of the die and plunger shoe, the plane of the section being indicated by the line 44 of Figure 3.

' Figure 5 is a vertical sectional end view of the die and aportion of the plunger, the plane of section being indicated by the line 5--5 of Figure 4.

Figure 6 is a perspective of a portion of the die and plunger shoe illustrating a partially formed or folded carton blank, the right-hand portion of the carton blankbeing broken away to reveal details of the plunger shoe construction.

Figure 7 is an outer side elevation of a folded and locked carton corner, the figure showing, to an enlarged scale, the outside of the lower left-hand corner of the carton blank illustrated in Figure 2 when folded.

Figure 8 is a sectional view of a folded and locked carton corner looking toward the inside face of the upper left-hand corner of the carton blank illustrated in Figure 2 when folded.

' Figure 9 is a plan view of the lower left-hand corner of i the carton blank illustrated in Figure 2 with folding and locking substantially completed and showing a portion of the boot member as it forms an opening in the carton wall and directs the locking tab therethrough.

The machine is bi-laterally symmetrical about a central vertical plane located between a pair of ground-engaging supports 11 as appears in Figure 1. Thus, a description of the structure on the left-hand side of the machine serves equally to describe the corresponding members on the" right-hand side of the machine.

Mounted vertically on the ground-engaging supports 11 is a pair of spaced parallel stanchions 12 forming between them a vertically elongated recess or track 13 in which slides an elongated block 14, the block being urged into uppermost position by a spring 16 secured to the block by a fastening 17 located at the bottom of the block, the spring being mounted at its upper end, by a suitable fastening 18, on the outer projection of a cross brace 19 supported by a block 20 spanning the stanchions 12. At the lower end of the track 13 is a sound deadening pad 21 capable of absorbing the shock incurredas the bottom end of the slidable block 14 impinges against the pad 21 at the bottom of the blocks travel. The block 14 is constrained against moving inwardly toward the center of the machine by a vertical plate 22 mounted at its lower end 23 on the support 11 and having a vertical elongated slot 24 formed therein to receive and guide in vertical reciprocable motion a plunger cross bar 26 mounted at opposite ends on the corresponding elongated block 14. It can be seen that as the plunger cross bar 26 is depressed by muscular power or other form of prime mover such' as a pneumatic or hydraulic plunger and cylinder mechanism, the block 14 is correspondingly lowered ina vertical direction at least until stopped by abutment with the sound deadening pad 21. At this juncture, downward force is removed and the spring 16 is elfecttive to restore to uppermost position the block 14 and the plunger cross bar 26. Accurate vertical translation of the plunger and cross bar 26 is assured by careful configuration and dimensioning of the vertically elongated slots 24 and cross bar 26.

Mounted centrally on the plunger. cross bar 26 and depending downwardly therefrom is a plunger arm 27 terminating at its lower end in an enlarged block or plunger shoe 28. The bottom face 31 of the plunger shoe is substantially rectangular in shape and is preferably elongated in a direction transversely with respect to the machines plane of symmetry. The central portion 33 of the elongated plunger side walls 32 are substantially vertical. Adjacenteach end of the sides 32, however, a tapered recess 34 is provided, the taper inclining from the outer side of the bottom face 31 upwardly and inwardly and Y at ect; 16, f .1 58;

reaching its maximum extent where the tapered wall 36 intersects the upper face 37 of the plunger shoe, the taper forming a triangular shaped recess end wall 38 as appears most clearly in Figures 1, and 6. In a somewhat comparable fashion, the end faces 41 of the plunger shoe are also tapered upwardly and inwardly from the outer ends of the bottom face 31 to provide a wedge shaped recess 42, or relief, and as most clearly is shown in Figures 3 and 4.

The elongated bottom face 31 of the plunger is adapted to engage with and urge downwardly into the machine a carton blank 46, a plurality of the carton blanks 46 being conveniently stored on an apron 47, or tray, mounted on the front of the machine and supported on each side by a pair of struts 48. On opposite sides of the apron is provided a pair of guide walls 49 mounted on the front side of the vertical plate 22 and projecting outwardly therefrom, The guide walls are spaced apart a distance sufficient to receive the carton blanks placed lengthwise therebetween and serve to assist the operator in guiding and directing the carton blanks 46 to the proper position over a carton forming die, generally designated by the numeral 51. A back plate 52 on the rear side of the die serves to locate the carton blanks properly over the die in a fore and aft position.

As the plunger shoe is urged downwardly into engagement with the carton blank 46 properly located over the die, and further downward motion is thereupon imparted to the plunger shoe, the carton blank is forced downwardly through a central vertical aperture 53, or opening, in the die 51, the vertical aperture 53 being defined by die shoulders and walls now to be described, and into engagement with various other elements which act in relation to and co-operation with the descending plunger to fold and lock the carton blank into carton or box form.

The central vertical aperture 53 in the die 51 is horizontally elongated in shape and is bounded on each side by a symmetrically disposed first pair of side shoulders 56 inwardly and downwardly curved in an arcuate fashion smoothly to merge with a corresponding pair of vertical side walls 57 or side faces of the die, as appears in Figures 3, 4 and 5. The first pair of shoulders fold the carton side walls, designated 58. Straddling each of the arcuate shoulders 56, and at each end thereof, is a second pair of side shoulders 61, or flap-folding shoulders, the second shoulders 61 somewhat resembling in contour the first shoulders 56 and serving to fold the carton flaps 59. The uppermost surfaces 62 of the second shoulders, however, in order to fold the carton in proper sequence, are disposed at an elevation slightly below the elevation of the upper surface 60 of the first shoulders 56, and as most clearly appears in Figure 4. Additionally, the radius of curvature of the second or flap-folding shoulders 61 is somewhat less than the radius of curvature of the shoulder 56. Thus, while upward folding of the flaps of the carton blank does not take place until after upward folding of the side panels of the carton blank has occurved, owing to the reduced radius of curvature of the flap-folding shoulders the rate of folding of the flaps is greater than the rate of folding of the side panels of the carton blank and proper carton folding sequence is thereby maintained.

At opposite ends of the die, a pair of symmetrically disposed end shoulders 66 is provided. The outermost ends of the end shoulders 66 are at substantially the same height as the top surface 62 of the shoulders 61, but, as appears most clearly in Figure 4, each of the shoulders 66 tapers inwardly and downwardly over a linear portion 67 and, upon approaching the central aperture 53, assumes an arcuate form inwardly and down.- wardly curved so as to merge smoothly with a vertical end wall 68 or end face of the die.

In order to direct into locking engagement the locking elements on the carton blank, a pair of rocker arms 81 is pivotally mounted within a corresponding pair of recesses 82 formed in each end of each of the shoulders 56. The rocker arms, which are boot shaped in form, are disposed within the die in a symmetrical fashion and a description of one serves equally to describe the other. With especial reference to Figure 5, it can be seen that each rocker arm, or boot, comprises an upper and inner arcuate portion designated a knee 83 and a lower inner portion denominated a toe 84, the toe being urged into the central vertical die aperture 53 by a compression spring 85 suitably disposed in a recess 86 behind the toe 84. The extent of projection by the toe into the die aperture 53 is governed by the abutment between the upper outer portion 87 of the rocker arm and the vertical recess wall 88 and normally assumes the position indicated in Figure 5. As the plunger descends, with the carton elements folded about the plunger shoe, the inwardly projecting toe 84 is engaged and cammed or urged outwardly, against spring force, into retracted position in the recess 82. Since the rocker arm is pivotally mounted on a pivot pin 89, however, as the toe is retracted the knee portion 83 is rocked into projected position and into engagement with elements of the carton lock in a fashion now described.

The carton blank 46 includes not only the side panels 58 and flaps 59, which are foldably acted upon by the die side shoulders, but it also includes a pair of end panels 91 which are engaged and folded upwardly by the die end shoulders. The carton side and end panels are foldably connected to a bottom panel 92 having dimensions substantially identical with the width and length of the bottom surface 31 of the plunger shoe, and it is the bottom panel which is engaged by the bottom of the plunger shoe and urged downwardly through the die, the side panels 58 being folded about score lines 93 and the end panels being folded about score lines 94 as the plunger descends. The flaps 59 are not connected to the side panels 58 but, instead, are separated therefrom by a slot 96, or cut. The flaps 59 are connected, however, to the sides of the end panels 91 along fold lines 97. Each flap 59, furthermore, is provided with a diagonal slit 98 bounded by or defined by an upper face 99 and a lower face 101, the slit 98 partially cutting off or partially isolating from the flap 59 a triangular-shaped locking tab 102 having a root portion 103 and a tip portion 104. Adapted to engage and interlock with the tab 102 is a tongue 106 cut into the side panel 58, the tongue comprising an upper cut 107, a lower .cut 108 and a point 109 formed thereby, the point being directed toward the adjacent cut 96 and separated therefrom by a portion of the side panel designated a deflector wall 111.

With especial reference to Figure 4, it can be seen that as the plunger shoe descends and urges ahead of it the carton blank 46, the carton side panels 58 are first caused to fold upwardly about the fold lines 93 as hinges owing to the folding efiort exerted by the first or uppermost die side shoulders 56. Thence, as the plunger continues downwardly, the flaps 59 are folded upwardly, about the hinge lines 97, by the second pair of side shoulders 61. Folding of the flaps 59 is shortly followed by a slower or more gradual upward folding of the end panels 91 about the fold lines 94 caused by the die end shoulders 66. At this juncture, the carton has been caused to assume approximately the degree of folding shown in Figure 6 and the bottom outer edge of the plunger shoe, with the carton folded thereabout, has commenced to engage the toe 84 of the boot member 81, causing the toe 84 to retract from and the knee 83 to project into the vertical die aperture.

As can be seen by inspection of Figures 6 and 9, the inwardly projecting knee 83 engages and pushes inwardly the outer end of the vertical side panel, and in particular the portion 111 of the side panel between the tongue 106 and the cut 96 defining the end of the side panel. The deflector portion 111 is bent or deformed inwardly and into the adjacent tapered recess 34 in the plunger block. The tongue 106, however, is not bent inwardly under the panel deforming force of the knee, but, instead, is retained in its .pre-existing attitude owing to the backing furnished the tongue by a plate 116, or strip, mounted on the vertical central portion of the plunger side. The plate 116 extends horizontally outwardly toward each end of the plunger and terminates in atriangular-shaped tip 117 adjacent the point 109 of the carton tongue and on its inner side is smoothly faired or rounded, as appears most clearly in Figure 9.

Owing to the inward deformation or bending of the end portion 111 of the side panel and the retention in original position'of the tongue 106, the tongue and the adjacent end panel portion are caused to become separated or spaced apart, as shown in Figures 6 and 9, and to produce therebetween an opening 121, or gap or mouth into which the locking tab 102 on the approaching flap 59 can be inserted.

Provision is made for carefully guiding or directing the locking tab 102 into the opening 121 and for thereafter deforming the tip 104 of the tab so that a secure interlock is obtained. Onthe side of the knee 83 adjacent the tab 102 the knee is formed to a curved or' cammed surface 122. The shape of the curved surface 122 is such that as the flap 59 and tab 102 are swung into upright attitude, upon rounding the arcuate portion of the die end wall, the leading edge of the tab 102 is brought into engagement with the curved surface 122 and is warped or deflected or cammed inwardly by the surface until the leading edge of the tab impinges at an angle against the adjacent deflector panel portion 111. Thereafter, as the tab is still further swung into upright position the tabs leading edge is guided between the cammed surface 122 of the knee 83 and the deflector panel 111 and is led inwardly through the opening 121 between the'tongue and .the deflector panel where the curved rear surface of the tongue stiffening plate 116 co-operates with the deflector panel in directing the locking tab 102 to its proper ultimate location, as appears approximately in Figures 7 and 8.

The innermost portion of the knee is so located with respect to the tab 102 as the tab is swung into its upright position that very substantial inward force is exerted on the tab by the knee. The force, in fact, is suflicient so that the tab and particularly the outermost or pointed or tip portion thereof, and the unsupported portion adjacent the slit 98 is given a permanent inward deformation or set. As a consequence, when the tab has moved to a location entirely within the tongue opening and to a position slightly beyond where the slit 98 comes into registry with the upper tongue cut 107, the set imposed on the tab causes the tab to spring inwardly and to effect a secure lock between the portion of the panel end 111 which is adjacent the point 109 of the tongue and the root portion 103 of the locking tab 102.

Ordinarily, carton blanks are cut with very considerable precision and the various carton components are then converted by the shoulders and deflecting members into proper folded and locked relation. however, the cuts forming the tongue and the locking tab are not in proper relation and it becomes necessary to overbend, slightly, the carton end panels to assure that the matching cuts over-ride the necessary positions of registry with each other so that the tab can spring inwardly to interlocked position. Overbending of the carton end panel is secured by the provision on each die end wall, of a bending knuckle 131, somewhat similar in construction and operation to the rocking members or boots 81. Each knuckle 131 is rockably mounted on a pin 132 within a recess 133 in the end wall. Each knuckle comprises a toe 134 normally urged into the die aperture by a spring 136, but which, upon engagement with the plunger shoe is cammed into retracted position. As the toe retracts a knee portion 137 is urged into From time to time,

panel 91 effects 'a resultant overbending of the flap 59 and of the locking tab 102., In this fashion the tab is always moved into a position wherein the tab can spring inwardly and elfect interlocking with its co-operating cut in the panel end portion. For some types of cartons it is preferred to utilize not just one of the knuckles 131 on each end wall but to use a pair of knuckles on each end wall. In such case, the knuckles 131 are disposed at the sides of the end walls, and adjacent the corresponding one of the side shoulders 61 so that the overbending thrust is in a direct line with the flap 59.

Once folding and locking has been elfected, further I descent of the plunger serves no further carton converting purpose. As the plunger is moved to a position below the lower end of the die, however, the carton side panels, and particularly the carton end panels, spring slightly or bulge slightly outwardly and engage the bottom surface of the die so that as the plunger is withdrawn upwardly the completely formed and locked carton is stripped from the plunger, and falling downwardly, is immediately available for use. As is clearly shown in Figures 7 and 8, the slight outward bowing of the end panels not only serves to strip the carton from the machine, as described above, but also to impress an initial tension or force on the interlocking and sprung tab and which therefore serves to lock it in position even more tightly.

It is clearly to be noted that while the tip 104 of the locking tab 102 is deformed or sprung inwardly an amount sufficient to effect a secure and positive interlock, as appears in Figures 7 and 8, the tip 104 is not bent or warped inwardly to a considerable extent. Ordinarily, the amount of deformation is such that there exists a substantially face-to face relationship between the marginal portion of the tab 104 along the lower cut face 101, as shown in Figure 8, and the adjacent panel portion 111. Owing to the relatively close proximity between tab and panel the finished carton is rendered especially useful .in comparison with the cartons as folded by a number of the machines presently available, and which are formed so that the tips 104 are bent or deformed inwardly a considerable amount. The farther inwardly the tips 104 extend into the carbon interior, the greater is the interference in packaging the contents and the more the likelihood of damaging, as by puncturing, the contents. The relatively close tab fit obtained by the machine of our invention is therefore highly to be desired.

What is claimed is:

A carton folding and locking machine comprising a die and a plunger vertically movable through said die, said plunger including an elongated shoe having an uninterrupted rectangular bottom surface, a pair of end walls inclined upwardly and inwardly, a pair of side walls,

each of said side walls including a central vertical portion, and a pair of end portions inclined upwardly and inwardly, and a pair of backing blades mounted fiushly on said central vertical portion of said side walls and extending horizontally toward said opposite end walls and overrunning a fraction of said inclined portions of said side walls, said die including a pair of die end walls, and a pair of die side walls adapted to encompass said plunger, said die walls being interrupted only by a pair of end boots rockably mounted in recesses in said die end walls, the lower end of each of said end boots being outwardly urgeable into said recess in said die end wall by said plunger, the upper end thereof being inwardly engagement the end i g hle o a d the co resp nd ng in ined end l o recesses in each of said die side walls at a location adja-' cent to and removed iron; the adjacent end of each of said backing blades, each of said side boots including a toe po n xt ndi g nt th pa h of said pl n r, n

a knee portion normally located in said recess and being rockable toward said plunger to a location inwardly removed frorn the adjacent end of said backing blade as said plunger engages said toe portion and urges said toe portion into said recess, said knee portion of each of said die side wall boots being beveled on the side facing toward the adjacent one of said die end walls.

References Cited in the file of this patent UNITED STATES PATENTS 1,212,182 Brooks Jan. 16, 1917 2,516,624 Guyer July 25, 1950 2,580,189 Pagendarrn Dec. 25, 1951 2,627,791 Ringler Feb. 10, 1953 2,655,843 Baker et al. Oct. 20, 1953 

